A container accommodating food therein is sometimes sealed with paste. However, in order to open the container so as to use it as a container or in order to cook food in the opened container, it is desirable that the container be opened without being damaged. Hence the idea of passing a sealable band around the container. However, for a container in which a pair of corresponding sides on the upper and bottom surfaces, respectively, are not parallel with each other, a conventional straight band cannot provide a sufficiently stable sealing.
Particularly, an erectable container tends to expand from its predetermined folded shape due to a restoring force acting on the folded portions. When the container is used, for example, to cook the content therein, it is undesirable to retain the state of being folded by means of an adhesive or the like because there is the danger that the adhesive or the like would dissolve.
Further, an erectable container may be formed with a hole in the center of the upper surface due to a restoring force of the folded portions, but the following problems occur: the contents get polluted or a foreign substance could enter into the container through the hole.
Still further, in case the erectable container is subject to a shinkwrap process after it is filled with the content, it is desirable that a predetermined folded state is retained, even temporarily, at the time of the shrinkwrapping, which is not possible with a conventional container without using an adhesive or a sticky tape.